Explosion proof oil burner



Jan. 3, 1956 A. E. MATHEY EXPLOSION PROOF on. BURNER 2 Sheets-Sheet 1 Filed Jan. 19, 1952 1 I I! If I I I 1/ fl Ill/l 1 8 3 M m H I Q9000 H H H v N M e I 6 a a 4 I. 8 w a OUOOQ 060.0000. 8 .000 4 I 4///g/H a a a 4 a 4- 4 a 0 8 6 4 4 Jan. 3, 1956 A. E. MATHEY 2,729,233

EXPLOSION PROOF OIL BURNER Filed Jan. 19, 1952 2 Sheets-Sheet 2 to provide a mechanism in United State Mass., assignor to Scully Mass., a corporation of This invention relates to oil burners. concerned with that type of oil burner or sleeve type oil burner.

It is particularly known as a range This type of burner has a plurality of concentric perforatedshells whichrest vertically on a circular base having. Wicks therein, which wicks receive oil by gravity'feedfrom a source usually located fairly close to the burners.

While range oil burners are relatively low in cost and efficient in operation neverthelessthey have been found somewhat hazardous in use and many fires and considerable loss of life have been caused through their failure to operate properly atall times.

It is an object of this invention to provide a construction relating to the fuel oil supply mechanism which will completely eliminate one of the conditions which has heretofore been responsible for explosions and resulting fires in the operation of range burners. In the normal operation of the range burner, the shellsor sleeves become 'red hotand at this temperature arecapable of causing almost instantaneous and complete vaporization of liquid fuel as it is fed by gravityto thebase. After the fuel has been exhausted or cut off, the residual heat remainingin the sleeves after full flame operation will be suificient to cause vaporization of oil supplied thereafter, for a considerable period of time. Therefore, in the operation of these burners it has often happened that the user, upon refilling the fuel supply after unintentionally allowing it to become exhausted, will feed oil to the burner bases from which the flame has gone out but in which the bases and sleeves are still hot enough to cause immediate development of explosive vapors. These vapors then fill the stove or heater in which the burners are located and the useiyon attempting to relight the burners, will ignite the vaporsjthereby causing an exp'losion of dangerous proportions. Such explosions may not only injure the operator but also may rupture the fuel supply so that free oil may fall to the floor where it may be ignited.

Accordingly, it is an obpect of the present invention series witli'the fuel supply line which will insure that the temperature of the burner baseand sleeves at the time of extinguishtnent of the flame because of fuel exhaustion will be below that temperature at which new oil supplied thereafter can be readily vaporized. In other words, the present invention will make it impossible for explosive vapors to begenerated by the burner if fresh oil be supplied at any tim e after the flame of the burner has gone out. Of course, if the fresh'oil is supplied while a flame is still present, then there will be no hazard presented because any vapors created will simply augment the existing flame.

The concept on which my invention operates isto provide means for automaticallyfreducingthe fuel supply'at an appropriate time before it becomes exhausted to a degree which will permit the wick to continue lighted but with a very reduced flame. This reduced flame is so low that it will beunable to maintainthe previous "vapor :izin temperature of the sleeves'andbase. *Furtherniore, this low flame will'then 'contiriue to burn'foratimelong Withthe valves 22 and 24 open, normal maximum enough to permit the temperature of the sleeves and base to drop to a degree which will be below that capable of causing any appreciable vaporization of fuel. Thus, when the flame finally goes out after burning fora suitable time at the aforesaid reduced rate, the burner temperature will be so low that fresh oil may be added at any time thereafter without the possibility of the generation of explosive vapors. e

The nature of the invention will be more clearlyunderstood as the description goes forward with the aid of the accompanying drawings in which- Fig. 1 is a sectional elevation of a firebox containing two burners supplied by a conventional gravity feed oil supply. 1

, Fig. ,2 is an enlarged view of the oil reservoir withone form ofthe invention secured to the entrance end of the supply line.

. Fig. 2a is an enlarged detail of the invention as disclosed in Fig. 2. i

Fig. 3 is a modification in which the oil is fed to the two burners through separate supply lines. The invention is connected to the entrance end of the right-hand supply line only.

Fig. 3a is an enlarged detail of the invention shown in Fig. 3.

Fig. 4 shows a modification of the invention utilizing a small siphon tube. 1

Fig. 4a is an enlarged detail of the invention shown in Fig. 4.

Fig. 5 shows another form of the invention.

Fig. 5a is an enlarged detail of the invention shown in Fig. 5.

Fig. 6 is still another modification of the invention.

Fig. 6a is an enlarged detail of the invention shown in Fig. 6.

Fig. 7 is a section on the line 77 of Fig. 6a.

Referring to Fig. 1, a burner housing, ordinarily in the form of a stove or firebox, is shown diagrammatically at 2. In the stove are positioned a pair of burners of the sleeve type, numbered 4 and 6, which burners are carried in the usual manner by supports 8 and 10. Depending from each burner are conventional carbon legs 12 and 14. An oil reservoir 16, for supplying oil by gravity feed to the burners, is positioned conveniently adjacent the stove. The reservoir is connected to the burners by a fuel supply line 18 which leads to a valve manifold 20 in which are mounted a pair of conventional valves 22 and 24. Valve 22 controls the fuel supply flowing through pipe 28 to burner 4.

In accord with the usual practice, the reservoir 16 is supplied by an inverted oil bottle 3b which will produce an oil level that will vary between the maximum and minimum levels 32 and 34. The burner bases are adjusted vertically with respect to the reservoir so that oil will be supplied thereto at the correct level for proper combustion.

comas the ice bustion will be produced in burners 4 and 6 so long fuel level remains above the top of the standpipe 40 which standpipe constitutes the reservoir end of the fuel supply line 18. The construction described thus far is conventional and in ordinary practice up to the present, the burners will go out when the fuel level falls below the top of standpipe 40 because oil can then no longer flow into line 18. It is preferred that the reservoir be left with a small quantity of oil in the bottom below the standpipe, thereby eliminating the chance of sediment or water entering line18.

The connection of the standpipe with the reservoir 16 can be made in any manner desired but as disclosed herein it is affixed by a pair of nuts 42 and 44 which clamp the reservoir bottom betwenthem in fluid tight fashion. A gasket or washer may be used if necessary. The lower end of the standpipe is connected by the usual fittings 46 to the end of line 18.

A first form of the invention is disclosed in Figs. 2 and 2a. In this arrangement, the standpipe 48 is secured in position at the bottom of reservoir 16 by nuts 42 and 44. However, in addition, a small hole 48 has been drilled through one side of nut 42 and thence on through the wall of standpipe 48. Hole 48 is considerably smaller than the vertical hole 50 through the standpipe. Thus, when the time arrives that the oil in bottle 38 is exhausted and the oil level has dropped below the top of the standpipe so that no more oil can be fed through the major passage 50 to line 18, still a reduced supply of oil will continue to flow to line 18 and the burners through the small opening 48. Immediately upon this automatic reduction in the volume of oil, the flames of the burners will be correspondingly reduced.

The opening 48 is of such size that enough oil will pass to keep the burner flames alive but will insure that the flames and burning gases will be of such low heat content that the temperature of the burner sleeves cannot be maintained at their previous high level. Thus, while the oil is dropping from the level at the top of standpipe 40 to the level of passage 48, the burner shells will have ample opportunity to reach a reduced temperature below that required to produce vaporization of the oil in any dangerous degree. Different burners will require varying times of operation of the reduced flame to produce the lowered burner temperature. The time may be controlled by varying the vertical distance between the top of the the standpipe and the entrance to passage 48. In general, it may be said that when the burner is operated at the reduced flame level, twenty to thirty minutes will be ample time to secure the temperature reduction, but as a precaution, this time may be extended to an hour or more if deemed desirable. When, in due course, the oil level has dropped to a point just below the entrance to passage 48, the supply of fuel to the burners will be cutoff and the reduced flames will then go out. Should the user at any time after the extinguishment of the flames add a fresh supply of oil to reservoir 16, thereby raising the level above the top of standpipe 40 so that oil would be supplied in maximum quantity to the bases 36 and 38, no dangerous condition could develop because the temperature of the bases and burner shells would be so low as to preclude dangerous vaporization. Accordingly, upon the renewal of such oil supply, the user could then safely insert a lighted taper in the burners to re-ignite the wicks in the usual manner. Should the user replenish the oil supply while the level was between the top of standpipe 40 and the entrance to passage 48, thus raising the level above the top of the standpipe so that a full supply could again be furnished to the burners, no dangerous condition could develop because both burners would still be lighted and the flames would merely increase to their normal size as determined by the setting of valves 22 and 24. During the period that has just been described, the valves 27. and 24 have remained open in normal operating position.

The foregoing explanation with respect to the construction of Figs. 2 and 2a is equally applicable in principle to all of the other figures, namely, Figs. 3 to 7 inclusive. The details of the construction vary somewhat in these other forms and will now be briefly described. In all cases, however, the oil being fed to the burners is automatically reduced when the fuel level has fallen to the top of the standpipe and this reduced supply is thereafter continued for a period long enough to enable the burner to cool to a safe temperature while a reduced flame is still in operation.

In Figs. 3 and 3a, the standpipe 40 has an auxiliary port 52 a substantial distance below its top end. This port 52 is of less area than the principal port 50 so that automatic reduction in the burner flame occurs as soon as the fuel level has dropped below the top of the standpipe. The standpipe 40, however, in Figs. 3 and 3a is connected to a pipe 54 which feeds one burner only. A see- 0nd pipe 56 feeds the other burner. Pipe 56 has a standpipe 58, taller than standpipe 40 and does not have any auxiliary port 52. Thus, when the oil level drops below the top of standpipe 58, the burner fed by pipe 56 goes out while the other burner continues in full operation until the oil level drops below the top of standpipe 40, after which it goes on reduced feed as heretofore explained. This arrangement, by which one burner is allowed to go out and the other is put on reduced feed, has been found safe because if an additional supply of oil should be added to reservoir 16 to raise the level above the top of standpipe 58, thereby resupplying the extinguished burner before it had had a chance to cool off, then any vapors generated by this burner would be at once spread within a very few seconds to the other still lighted burner. These vapors would then be ignited but because of their limited quantity would produce nothing more than a minor puff which would re-ignite the unlighted burner. On the other hand, if the unlighted burner had cooled to a point where it was incapable of generating vapors in sufficient quantity to be ignited, then, of course, nothing would happen other than that there would be an oil supply in the burner base available for ignition by hand if the operator so desired.

In Figs. 4 and 4a, a further modification is disclosed in which the standpipe 40 has positioned therein a siphon tube 60, having its entrance end at 62 and its discharge end at 64. The opening through the siphon tube is much smaller than the annular space between the outside of tube 60 and the interior of the major passage 50. Thus, so long as the oil level is above the top of standpipe 40, oil will flow in suflicient volume to the burners to maintain the flames at a maximum degree. When the level drops below the top of the standpipe, oil will then continue to flow to pipe 18 through siphon tube 60 but in reduced volume so that the burner flames will be correspondingly reduced to permit the temperatures of the burners to fall to a safe degree before the oil level has dropped to a point where the siphon effect is broken.

Another form of the invention is shown in Figs. 5 and 5 a. In this instance, the standpipe comprises two portions, namely, the section 66 which is connected to pipe 18 and an additional tubular element 68 having a bottom extension 70 which extension fits into the upper end of pipe 66. A passage 72 extends vertically through member 68 and is of suflicient size to permit oil to flow in a quantity sufficient to maintain full flames at the burners. A smaller reduced passage 74 leads horizontally through the wall of element 68 into passage 72. A protective screening 76, in the form of a cylindrical hood, is positioned over the top of element 68, covering the entrances to passages 72 and 74 to prevent sediment from entering pipe 18. This screen, of course, is not essential to the invention but, on the other hand, it will be understood that screens might advantageously be used to cover all of the standpipes should conditions of dirty fuel supply require such filtering. When the oil level falls below the entrance to passage 72, the fuel supply, which will then flow through smaller passage 74, will be reduced to cause the flames to drop to a degree permitting the burners to cool to the required safe temperature before the oil level has fallen below smaller passage 74. It will be understood in the form shown in Figs. 5 and 5a that the pipe 66 plus the inserted element 68 together constitute the standpipe.

Still another modification is shown in Figs. 6 and 6a. Here the standpipe comprises a pipe 78 extending above nut 42 and having in addition an element 80 positioned on its top. Element 80 comprises a disc 82 (see Fig. 7) having radial slots 84 and 86 and a vertical tube 88. Tube 88 has a passage 90 therethrough which is large enough to supply fuel in sufficient volume to produce maximum flames at the burners. When the oil level falls below the top of disc 82 then the fuel supply to the burners is limited to the oil that can flow through slots 84 and 86 and thence downwardly through the annular space between the exterior of tube 88 and the interior of pipe 78. This T reduced quantity is such as to produce therequired diminished flames thatwill enable the burners to cool to a safe degree before the oil level has fallen below the top of pipe 78 at which time the flames will be extinguished.

In the various disclosures in Figs. 2 to 6a inclusive, it will be observed that the vertical distance between the entrance to the major passage and the entrance to the reduced passage varies. This distance may vary because of the difierence in the time required for the fuel level to fall from the entrance to the major passage to the minor passage. The rate of oil consumption will, of course, vary with the. size and numbers of burners being supplied and the volume consumed for a given vertical drop will vary with the area of fuel in the reservoir 16. With knowledge of the size of reservoirs, burners, vertical distances between the major and minor passages and the size of the passage openings, the parts may be so adjusted that in any given installation the time during which the reducedflame prevails will produce the desired final result, namely, that the temperature of the burner, or burners, will be reduced to a safe degree before the burner flame, or flames, is finally extinguished.

By the foregoing method and through the use of the means herein disclosed, I have provided a certain and economical way of completely eliminating one of the major fire hazards inherently present in oil burners of this type. The invention herein disclosed permits the user to add a new supply of oil to the reservoir at any time without consulting the condition and temperature of the burners. If the burners are still in full operation, the addition of a new jar of oil makes no change in the operation; if the burners are operating with a reduced flame due to the oil level being between the entrance to the major passage and the entrance to the minor passage, the addition of more oil to the reservoir will merely cause the flame to return to full operation. If more oil is added to the reservoir after the reduced flames have gone out, then such addition of oil cannot produce an explosive mixture within the stove as the burner temperatures will at that time be below the dangerous vaporizing degree. The user may then ignite the burners with a taper safely in the normal manner.

The present invention cannot function if the burners, while in normal operation, are shut off by the closing of their respective valves. On the contrary, the invention functions when the user intentionally or unintentionally allows the oil level to fall to a point where, without the incorporation of the invention, the burner would quickly go from full flame to out. Instead of the burners going out quickly, leaving them in a hot dangerous condition, the flames are automatically reduced and burn thereafter for a time long enough to allow the burner temperature to fall to a safe degree.

It is my intention to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.

I claim:

1. The combination of an oil burner, a reservoir for oil, an oil supply line connecting said burner and said reservoir, said supply line having its entrance end a short distance above the bottom of said reservoir, said entrance end being substantially vertical, a tube fitting within said entrance end and extending thereabove, a passage between said entrance end and tube of such less capacity than the passage through said tube that the oil supply to said burner will be substantially reduced as soon as the oil level has dropped below the top of said tube and to a degree that will permit the temperature of said burner to fall, while still in operation, to a temperature below that capable of causing appreciable vaporization of said oil.

2. The combination of an oil burner, a reservoir for oil, an oil supply line connecting said burner and said reservoir, said supply line having its entrance end in vertical position in the bottom of said reservoir, a tube affixed to said vertical end and extending thereabove, a

passage. etweensa dtube and the e ttaa eae d. .oftsa'id supply line located below the top of said tube whereby oil may flow to said supply line through said passage after the oil level has dropped below the top of said tube, said passage being small enough to cause reduction in said'oil supply so as to produce a low flame in said burner and the vertical distance between the top of said tube and the entrance to said passage being suflicient to provide time enough .while said burner remains lighted by the reduced. oil supply for the temperature of said burner to drop to a predetermined degree that is incapable of cansing appreciable vaporization of said oil before theoil level has fallen below the entrance to said passage.

$3.;v Thecombinationof an oil burner of the type having a conventional gravity feed oil supply system consisting. of afreservoir and a single oil supply line running directly from said reservoir to said burner and a device for preventing an explosionin said burner, said device comprising means connected to the entrance end of said supply line providing two entrances to said oil supply line, one of said entrances being above the other, the upper of said entrances being large enough to supply oil in full flame quantity and the lower of said entrances being small enough to cause reduction of said flame to a degree at which the temperature of said burner, prior to the exhaustion of oil entering said supply line through said lower entrance, will reach a temperature below that at which oil vapors will be generated freely when oil is present in said burner.

4. Means for preventing an explosion in an oil burner, said means comprising a single oil supply line, a reservoir for oil, said supply line being connected to said reservoir and having its entrance end a short distance above the bottom of said reservoir, said entrance end being substantially vertical, a tubular auxiliary member fitting within said entrance end to provide an oil passage therebetween, said auxiliary member having a transverse extension resting on the end of said supply line, a passage between said entrance end and said transverse extension of less capacity than the passage through said tubular auxiliary member whereby the oil supply to said burner will be substantially reduced as soon as the oil level has dropped below the top of said tube.

5. The combination of an oil burner of the type having a conventional gravity feed oil system consisting of a reservoir and a single oil supply line running directly from said reservoir to said burner, and a device for preventing an explosion in said burner, said device comprising means for automatically supplying oil to said burner at a reduced rate following exhaustion of the normal oil supply for a period long enough to permit said burner to reach a temperature below that capable of causing appreciable combustible vaporization of said oil, said means comprising a standpipe extending above the bottom of the oil supply reservoir, said standpipe having therein the major entrance to said oil supply line and another passage having its entrance located below said major entrance and leading to the said oil supply line, said other passage being smaller than the minimum dimension of said oil supply line whereby said oil supply to said burner will be reduced as soon as the oil level has dropped below the level of said major entrance.

6. The combination of an oil burner of the type having a conventional gravity feed oil supply system consisting of a reservoir and a single oil supply line running directly from said reservoir to said burner, and a device for preventing an explosion in said burner, said device comprising means for automatically supplying oil to said burner at a reduced rate following exhaustion of the normal oil supply for a period long enough to permit said burner to reach a temperature below that capable of causing appreciable combustible vaporization of said oil, said means comprising a pipe at the reservoir end of said oil supply line, a tubular auxiliary member in series with said pipe and extending above the end of said pipe, said pipe and auxiliary member together forming a standpipe of sufficient capacity to provide maximum fuel requirements for said burner, a passage of reduced dimensions between said pipe and said auxiliary member for automatically reducing the oil supply to said burner after said oil level has dropped below the top of said auxiliary member.

7. In combination with an oil burner, a reservoir for supplying oil to said burner, and a supply line connecting said burner and said reservoir and having its entrance end substantially vertical and terminating a short distance above the bottom of said reservoir, means for preventing an explosion in said burner comprising, an elongated element provided with an axial passageway fitting within said entrance end and forming with said entrance end an annular passageway communicating with the interior of said supply line, one of said passageways terminating within said reservoir at a level higher than the level at which the other of said passageways terminates, the passageway terminating at the higher level being of larger capacity than the passageway terminating at the lower level, the passageway terminating at the lower level being of such lesser capacity that when the oil level in the reservoir drops below the level at which said passageway of greater capacity terminates, the oil supply to said burner will be reduced to a degree that will permit the temperature of said burner to fall while said burner is still in operation to a temperature below that capable of causing appreciable combustible vaporization of said oil.

References Cited in the file of this patent UNITED STATES PATENTS 1,470,775 Stephens Oct. 16, 1923 2,086,884 Sherman July 13, 1937 2,269,848 French Jan. 13, 1942 2,314,802 Skerritt Mar. 23, 1943 2,601,894 Morse July 1, 1952 

